His office says reports that the cap will be set at 25% are "wide of the mark" but nonetheless it appears a limit on the size of a bank will be one of his key proposals.

He's due to make a big speech on the economy on Friday - and, at a time when the economy is improving and the Tories are eating into Labour's poll lead, Mr Miliband needs to find a new political message that will resonate with voters.

And after a stumble during PMQs when he suggested there is a difference between a quarter of a million and 250,000 - he's having a tougher time in 2014 than he had at the end of 2013.